A new report by the Environmental Agency Wales has placed one in six properties at risk of flooding
One in six properties in Wales is at risk of flooding, according to the most detailed assessment yet drawn up by Environment Agency Wales.
The figures are much higher than in previous estimates because the threat from surface water flooding is included for the first time.
The report suggested 600,000 people in Wales live or work in flood risk areas.
It also outlined the work needed to "manage risk", including building new flood defences in areas of high risk.
Geraint Davies, chair of Flood Risk Management Wales, said: "Climate change means that the number of us at risk from flooding in Wales has risen to one in five or 600,000 people.
Here in Wales there are important decisions for us to take about how to manage these risks...
Chris Mills, Environment Agency Wales
"This means we must redouble our efforts to adapt Wales to climate change by spreading awareness, providing defences and preventing inappropriate development.
"We must act within an overview of all types of flooding - river, coastal and surface flooding - working alongside local authorities to make best use of public money to manage the growing risk to Welsh communities."
Last year, Environment Agency Wales estimated the number of properties in Wales at risk of flooding from rivers and the sea at 170,000. That figure is now put at 222,000.
The agency said rising sea levels and increasingly severe and frequent rain storms caused by climate change meant the risk of flooding would increase even further.
The cost of damage annually to homes and businesses in Wales is estimated at around £200m.
Chris Mills, Environment Agency Wales director, said: "The latest UK climate change data shows that the risk of flooding will continue to increase in future due to rising sea levels and more frequent and heavy storms.
"Here in Wales, there are important decisions for us to take about how to manage these risks to protect people, communities, businesses and the Welsh economy in future."
The agency's report outlined the work already done to prepare for flooding but also highlighted further work required.
This included helping people to be better prepared and preventing "inappropriate development" in flood plains.
The agency said it would be investing more than £16m on its capital programme this year, much of it on building new defences.
"Over the last five years we have completed a number of flood improvement works which has reduced the risk of flooding to nearly 6,000 extra properties across Wales as well as protecting key infrastructure," said Mr Mills.
"Whilst continued investment in managing these risks is crucial, we cannot always prevent flooding so communities need to take responsibility for being prepared, for example by signing up to our free flood warning service."
Recent climate change forecasts from the Met Office suggested Wales could face an increased risk of flooding as sea levels rose.
Environment Minister Jane Davidson said action was needed to limit the potential damage of climate change in the future.
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